Ozone is a gas whose molecules are composed of three bonded oxygen atoms. Ozone is a highly reactive substance, which is used to treat drinking water and swimming pool water, treat industrial waste, and to bleach inorganic products such as clay. Ozone is the second most powerful oxidant after fluorine. It is also a powerful disinfectant.
Ozone may be created by any process which breaks apart diatomic oxygen molecules. The free oxygen atoms thus created react with un-broken diatomic oxygen molecules to create ozone. Of the many methods used to make ozone, only two are of commercial importance: UV radiation and corona discharge.
The radiation of air by ultraviolet (UV) light creates ozone at up to 0.25% by weight concentration in air. A 40-watt ultraviolet light bulb can produce 0.5 gm/hr of ozone. Ultraviolet ozone generation is used for food preservation and in air ducts. Creating ozone with ultraviolet radiation is relatively inefficient. It has been proposed to ozonated water in a reservoir by treating air with UV and then bubbling the air through a tank or other reservoir of water; however, such attempts to ozonate water in this manner have proven unsuccessful.
Greater quantities and higher concentrations of ozone are provided by corona discharge compared with ultraviolet ozone generation. Corona discharge is about 2 1/2 times as efficient as ultraviolet light in terms of energy.
Physically, a corona discharge ozone generator consists of two parallel electrodes (metal plates) held parallel to each other and subjected to a high voltage alternating current. A layer of dielectric usually covers one of the electrodes. The electrodes are typically either a sandwich of flat plates or concentric cylinders. Electrons traveling between electrodes collide with oxygen to create the ozone.
The amount of ozone generated varies exponentially with the voltage and directly with the frequency of the oscillating current. Frequencies up to 2000 hertz are used but many ozone generators work at line frequencies of 50 or 60 hertz. A high-frequency ozone generator will produce seven times as much ozone per electrode area and yield twice the ozone concentration as compared to a low frequency ozone generator. With line frequencies, a simple transformer may be used to increase the working voltage; higher frequencies may require choppers, oscillators, or the like, plus a transformer. The maximum working voltage is about 20,000 volts RMS. Lower voltages with higher frequencies generate more ozone with less chance of burning out the electrodes.
U.S. Pat. No. 4,485,513 to Collier shows an ozone cleaning system, which comprises an ozone producing unit 21 and a cleaning head connected by conduits. A blower forces air through the ozone unit and into the head, where it deodorizes carpets and the like.
The Collier device is not a vacuum cleaner and employs no air pump, except for a blower that directs ozone down to the cleaning head through the pipes 47. The motor M, seen in FIG. 1, drives a cleaning disk 11 (best seen in FIG. 2A) and is not connected to any turbine or suction device.
E. H. Yonkers, Jr., in U.S. Pat. No. 2,297,933, shows a suction cleaner which incorporates a device for electrically charging dust particles which have passed through the filter bag of the cleaner. The charged particles of dust are attracted to an oppositely charged plate. The electrical apparatus acts to ozonize (create ozone in) the air as well as to electrostatically precipitate dust.
U.S. Pat. No. 5,185,903 to Choi also shows a vacuum cleaner with an ozonizer within the exhaust path of the air. Ozone does not contact with the surface being cleaned.
Bargeboer, U.S. Pat. No. 2,242,163, discloses a vacuum cleaner similar to that of Choi and Yonkers, Jr., which incorporates an ozone producer upstream of the filter. Ozone does not contact with the surface being cleaned. Bargeboer also discloses the use of ultraviolet rays to produce ozone.
All the above devices suffer from the drawback of introducing ozone directly into the air, which is typically then dispersed within an enclosed space. Ozone is a strong irritant as well as being a disinfectant and deodorizing agent. As little as one part per million of ozone in air will cause irritation to the eyes and throat. Higher concentrations will affect mental awareness and health.
U.S. Pat. No. 4,834,948, issued to Schmiga et al, discloses an ozone-producing device including an electrode disposed within a quartz tube. The electrode is fed with high frequency alternating voltage to produce ozone in air flowing within the quartz tube. The quartz tube is surrounded by a water jacket in which cooling water flows. The water in the jacket is irradiated by ultraviolet light from the electrode, which passes through the quartz tube and, according to Schmiga et al, sterilizes the water.
FIG. 8 of Schmiga shows its system for purifying the water in a swimming pool 81. Pool water is passed through the cooling jacket in the ozonizer 83. Ozonized air is fed to a "venturi pump" 85, where it is mixed with water (column 6, line 56); a compressor can be used in place of the venturi pump (column 7, line 1), which implies that the "venturi pump" of Schmiga creates a positive pressure rather than a negative pressure, as do devices usually described by the word "venturi". Schmiga does not disclose a compressor for injecting ozonized air into a water stream.
Because of the slight concentration of dissolved oxygen in water, the Schmiga devise does not produce appreciable quantities of ozone in the cooling water within the water jacket surrounding the quartz tube, although Schmiga et al hint that this is so (column 6, lines 60-64).
The prior art does not disclose any device which places ozone in contact with the object being cleaned and which simultaneously cleans the object by means of vacuum and/or vacuum combined with other cleaning methods.
Neither does the prior art disclose any cleaning apparatus for use in enclosed inhabited areas, which does not release large amounts of ozone into the air to irritate persons in the vicinity.